Phosphogypsum significantly alters root growth and fungal colonization of smooth brome and sheep fescue on a reclamation site

Abstract

Phosphogypsum (PG) is a by-product of phosphate fertilizer production. This study is the first to investigate Bromis inermis and Festuca ovina root morphology and colonization with arbuscular mycorrhizal fungi and dark septate endophytes (DSE) in pure PG and PG with a soil cap (soil). Root length density was significantly lower for plants on PG than on soil and both plant species were colonized with AMF and DSE, with lower frequency and intensity in PG. Phosphorus (20 times), calcium (35 times) and sulphur (50 times) were significantly higher in PG than in soil; resulting higher root tissue concentrations were significantly negatively correlated with mycorrhizal colonization for Festuca but not Bromus. Higher fungal colonization of Bromus, especially with DSE known to be prevalent in extreme environments, may be responsible for its better performance on PG relative to Festuca.